California’s housing affordability crisis is progressively getting worse. It has now plummeted to its lowest level in 10-years, and less than one in five households can afford to purchase a median-priced single-family home in the Bay Area, according to new data released by the California Association of Realtors (CAR).

CAR released its second-quarter Housing Affordability Index report (HAI), based on the percentage of all households that can afford to purchase a median-priced, single-family home in the state. CAR also reports affordability indices for regions and counties within the state. The index is regarded as the most fundamental benchmark of housing well-being for home buyers.

The percentage of homebuyers who could afford to buy a median-priced, existing single-family home in the state declined from 31 percent in the first quarter to 26 in the second quarter; in the previous year, the index was at 29 percent, according to CAR’s HAI.

The second quarter marked the 21st consecutive quarter that CAR’s HAI printed below 40 percent; the index topped at 56 percent in the first quarter of 2012.

The report showed that prospective homebuyers would need to have minimum annual income of $126,500 to prequalify for the purchase of a $596,730 statewide median-priced, existing single-family home in the second quarter. Assuming a 20 percent down payment and an effective composite interest rate of 4.70 percent, the monthly payments of a 30-year fixed-rate loan would be around $3,160.

The California counties that recorded 10-year lows in housing affordability were Alameda, Merced, Orange, Riverside, Sacramento, San Bernardino, San Diego, San Mateo, Santa Clara, Santa Cruz, and Sonoma.

Here are the areas where housing affordability is at crisis levels: Santa Cruz (12 percent), San Francisco, San Mateo, and Mono (all at 14 percent), and Alameda and Santa Clara (both at 16 percent).

According to CAR’s index, the most affordable counties in California during the second quarter were Lassen (64 percent), Kern (53 percent), Madera (52 percent), Tehama (51 percent) and Kings (50 percent).

Housing Affordability Peaked At 1Q 2012

Housing Affordability — Traditional Index

Affordability Peak vs. Current

Minimum Annual Income Required During Affordability Peak vs. Current

Monthly PITI During Affordability Peak vs. Current

In a separate, but relevant report from CAR, data shows California’s real estate market could have already peaked.

California Home Sales Declined for the 1 st Time in 4 Months

Sales Lost Momentum as Mortgage RatesContinued to Climb

California is one of the largest housing markets in the nation, as it has been a forward leading indicator for the rest of the country. Amid a housing shortage, which has blossomed into a housing affordability crisis, sales this summer have started to tumble, even as more inventory comes online. The supply of homes for sale increased annually in June for the first time in three years, according to the National Association of Realtors, which has depressed sales for the third straight month.

And now it seems, California’s real estate market could be in the beginning stages of a correction to fair value, after nearly a decade of speculation forced much of the median-priced single-family homes out of reach of the middle class – contributing to the housing affordability index at a 10-year low.